package org.g4studio.core.net.telnet;

/**
 * The TelnetCommand class cannot be instantiated and only serves as a
 * storehouse for telnet command constants.
 * 
 * @author Daniel F. Savarese
 * @see org.apache.commons.net.telnet.Telnet
 * @see org.apache.commons.net.telnet.TelnetClient
 */

public final class TelnetCommand {
	/*** The maximum value a command code can have. This value is 255. ***/
	public static final int MAX_COMMAND_VALUE = 255;

	/*** Interpret As Command code. Value is 255 according to RFC 854. ***/
	public static final int IAC = 255;

	/*** Don't use option code. Value is 254 according to RFC 854. ***/
	public static final int DONT = 254;

	/*** Request to use option code. Value is 253 according to RFC 854. ***/
	public static final int DO = 253;

	/*** Refuse to use option code. Value is 252 according to RFC 854. ***/
	public static final int WONT = 252;

	/*** Agree to use option code. Value is 251 according to RFC 854. ***/
	public static final int WILL = 251;

	/*** Start subnegotiation code. Value is 250 according to RFC 854. ***/
	public static final int SB = 250;

	/*** Go Ahead code. Value is 249 according to RFC 854. ***/
	public static final int GA = 249;

	/*** Erase Line code. Value is 248 according to RFC 854. ***/
	public static final int EL = 248;

	/*** Erase Character code. Value is 247 according to RFC 854. ***/
	public static final int EC = 247;

	/*** Are You There code. Value is 246 according to RFC 854. ***/
	public static final int AYT = 246;

	/*** Abort Output code. Value is 245 according to RFC 854. ***/
	public static final int AO = 245;

	/*** Interrupt Process code. Value is 244 according to RFC 854. ***/
	public static final int IP = 244;

	/*** Break code. Value is 243 according to RFC 854. ***/
	public static final int BREAK = 243;

	/*** Data mark code. Value is 242 according to RFC 854. ***/
	public static final int DM = 242;

	/*** No Operation code. Value is 241 according to RFC 854. ***/
	public static final int NOP = 241;

	/*** End subnegotiation code. Value is 240 according to RFC 854. ***/
	public static final int SE = 240;

	/*** End of record code. Value is 239. ***/
	public static final int EOR = 239;

	/*** Abort code. Value is 238. ***/
	public static final int ABORT = 238;

	/*** Suspend process code. Value is 237. ***/
	public static final int SUSP = 237;

	/*** End of file code. Value is 236. ***/
	public static final int EOF = 236;

	/*** Synchronize code. Value is 242. ***/
	public static final int SYNCH = 242;

	/*** String representations of commands. ***/
	private static final String __commandString[] = { "IAC", "DONT", "DO", "WONT", "WILL", "SB", "GA", "EL", "EC",
			"AYT", "AO", "IP", "BRK", "DMARK", "NOP", "SE", "EOR", "ABORT", "SUSP", "EOF" };

	private static final int __FIRST_COMMAND = IAC;
	private static final int __LAST_COMMAND = EOF;

	/***
	 * Returns the string representation of the telnet protocol command
	 * corresponding to the given command code.
	 * <p>
	 * 
	 * @param code
	 *            The command code of the telnet protocol command.
	 * @return The string representation of the telnet protocol command.
	 ***/
	public static final String getCommand(int code) {
		return __commandString[__FIRST_COMMAND - code];
	}

	/***
	 * Determines if a given command code is valid. Returns true if valid, false
	 * if not.
	 * <p>
	 * 
	 * @param code
	 *            The command code to test.
	 * @return True if the command code is valid, false if not.
	 **/
	public static final boolean isValidCommand(int code) {
		return (code <= __FIRST_COMMAND && code >= __LAST_COMMAND);
	}

	// Cannot be instantiated
	private TelnetCommand() {
	}
}
